We are a commune of inquiring, skeptical, politically centrist, capitalist, anglophile, traditionalist New England Yankee humans, humanoids, and animals with many interests beyond and above politics. Each of us has had a high-school education (or GED), but all had ADD so didn't pay attention very well, especially the dogs. Each one of us does "try my best to be just like I am," and none of us enjoys working for others, including for Maggie, from whom we receive neither a nickel nor a dime. Freedom from nags, cranks, government, do-gooders, control-freaks and idiots is all that we ask for.
There is obviously a correlation between muscle mass and strength for the "strong men," but for ordinary men and for women, not so much. It's common for me to see young women in the gym, with no notable muscle mass, outlifting me in squats and even in deads.
What do we consider low reps? Low reps are when you can only do 3-8 reps. Higher reps are 10-20. I would never do high reps with powerlifts. Arms, yes. Calisthenics like pushups, for sure.
I would have liked to see before and after muscle biopsies on both groups. I suspect the compositional changes would be much different with the low load group experiencing primarily increases in mitochondrial volume and the high load group showing sarcoplasmic growth.
Of significance, it does not appear that the low load group experienced a loss of strength.